Alfa 166 Transmission Grinding Points to Failed Radiator

Had similar transmission symptoms on a 2005 Alfa 159 with the 2.2L engine. Rough shifting and grinding turned out to be a faulty transmission control module connector. The cooling fan was also affected since the control unit manages transmission oil cooler function. Initial diagnosis pointed to radiator coolant issues, but leak detection showed the real problem was electrical. The connector had corroded pins causing intermittent connection loss. This triggered limp mode and warning lights since the transmission control unit couldn't properly read temperature and shift sensors. The repair involved cleaning the connector terminals, applying dielectric grease, and securing the wiring harness. A diagnostic reset was needed after fixing the connection. While not mechanically severe, leaving it unfixed could have led to transmission damage from improper cooling and shift control. Given your symptoms match, rough shifts, warning lights, limp mode, checking the control module connections should be the first step before assuming internal transmission problems. The transmission behavior often improves immediately once proper electrical contact is restored.

Thanks for the detailed explanation about the control module fix. After reading your post, I had my Alfa 166 checked and the mechanic found a similar connector issue affecting both transmission and cooling system performance. The pressure sensor was also damaged which affected coolant flow. Did you ever experience any car overheating problems after getting it fixed? Also, curious about the repair costs in your case? Mine came to 380 Euro including parts and labor, but wondering if I paid too much since prices vary.

Since fixing the faulty radiator oil pressure sensor and connectors, my Alfa has been running perfectly with no overheating issues. The cooling system now maintains proper pressure levels and the transmission shifts smoothly. The total repair cost in my case was only 95 Euro, which covered diagnosing and fixing the cable connection to the pressure sensor. The cooling system now works as designed, regulating both engine and transmission temperatures effectively through the oil cooler circuit. Your 380 Euro bill seems a bit high compared to my repair, but if they replaced the pressure sensor along with fixing connectors and performed a full diagnostic scan, the cost difference makes sense. A properly functioning pressure gauge is crucial for both transmission and engine cooling performance. The key was catching the issue early before it could cause more serious damage to the transmission or cooling components. Regular monitoring of pressure readings and coolant levels helps prevent future problems.

Here's my story after getting it all fixed. The proper radiator coolant pressure restored smooth gear shifts, and the grinding noise completely disappeared. The mechanic I went to specializes in transmission control systems and quickly identified the connector issue plus the faulty pressure sensor. The 380 Euro repair cost included new connectors, pressure sensor, and a full system diagnostic. No car overheating issues since the fix three months ago. The transmission warning lights cleared up immediately after the repair and haven't returned. The mechanic also showed me how a single bad connector was causing multiple system failures. They pressure tested the entire cooling system during repair to ensure no hidden coolant leaks remained. Much better experience than my previous shop that misdiagnosed the problem. Really glad I asked for advice here before assuming the worst about transmission internals. Saved me from an unnecessary transmission rebuild that another shop had quoted at over 2000 Euro.